26 July 2015

Population distribution and inequality

wards_SA_ordered <- readRDS("RDS/wards_SA_ordered.rds")
wards_SA_ordered@data$DENSITY <- round(wards_SA_ordered@data$DENSITY, digits=1)

The distribution of population density accross South Africa is very skewed. Mean population density in South Africa is 42.4 people/km2. Another consideration is the unequal distribution of electricity (which is less kWh/person now than it was at the end of Apartheid in 1994.

library(ggplot2)
ggplot(aes(x=DENSITY),data=wards_SA_ordered@data) + geom_histogram(binwidth=1000,color="white") +
  ggtitle("Population density in South Africa's 4277 Wards") + labs(x="Density in people/sq km",y="Number of wards")

South Africa at night from the VIIRS polar orbit satellite without a ward population density choropleth overlay

What the choropleth overlay looks like with the threshold at the 50th percentile of ward population density

What the choropleth overlay looks like with the threshold at the 70th percentile of ward population density

What the choropleth overlay looks like with the threshold at the 95th percentile of ward population density